Safeguard your 21700 battery packs with these flame retardant spacers, designed to prevent short circuits and contain potential battery fires. These spacers ensure proper separation between cells while maintaining optimal airflow for efficient battery pack performance. This pack includes 2 spacers, with size options to suit a variety of 21700 cells. Main Features: Constructed from flame retardant plastic for superior safety Prevents fire from spreading between battery cells Keeps 21700 batteries securely separated Maintains correct spacing for better battery pack performance Easy to install and reusable Size Options: 21.2mm – Fits most Samsung, LG, Murata 21700 cells, including Lishen LR2170LA 21.7mm – Fits most other Lishen models and 21700 cells Specification: Material: Flame retardant plastic Compatible with: 21700 batteries Safety: Reduces risk of fire propagation